diff options
author | Pragnesh Patel <pragnesh.patel@sifive.com> | 2020-11-14 14:42:34 +0530 |
---|---|---|
committer | Heiko Schocher <hs@denx.de> | 2020-11-28 08:30:41 +0100 |
commit | b2d4cbe6d47a7685c66517edd265a78dfc8b9c98 (patch) | |
tree | c37b2f46dfcaed4f7e5a5fc4c6eb0ee0524df365 /drivers | |
parent | 942012246a7a1dea66869be7763d73f0565bdb7b (diff) |
i2c: ocores: add i2c driver for OpenCores I2C controller
Add support for the OpenCores I2C controller IP core
(See http://www.opencores.org/projects.cgi/web/i2c/overview).
This driver implementation is inspired from the Linux OpenCores
I2C driver available.
Thanks to Peter Korsgaard <peter@korsgaard.com> for writing Linux
OpenCores I2C driver.
Signed-off-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/i2c/Kconfig | 7 | ||||
-rw-r--r-- | drivers/i2c/Makefile | 1 | ||||
-rw-r--r-- | drivers/i2c/ocores_i2c.c | 637 |
3 files changed, 645 insertions, 0 deletions
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 8ae54e1e93b..37958083af9 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -342,6 +342,13 @@ config SYS_I2C_NEXELL have several I2C ports and all are provided, controlled by the device tree. +config SYS_I2C_OCORES + bool "ocores I2C driver" + depends on DM_I2C + help + Add support for ocores I2C controller. For details see + https://opencores.org/projects/i2c + config SYS_I2C_OMAP24XX bool "TI OMAP2+ I2C driver" depends on ARCH_OMAP2PLUS || ARCH_K3 diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index b37198036c0..1aac5c481e2 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_SYS_I2C_MESON) += meson_i2c.o obj-$(CONFIG_SYS_I2C_MVTWSI) += mvtwsi.o obj-$(CONFIG_SYS_I2C_MXC) += mxc_i2c.o obj-$(CONFIG_SYS_I2C_NEXELL) += nx_i2c.o +obj-$(CONFIG_SYS_I2C_OCORES) += ocores_i2c.o obj-$(CONFIG_SYS_I2C_OCTEON) += octeon_i2c.o obj-$(CONFIG_SYS_I2C_OMAP24XX) += omap24xx_i2c.o obj-$(CONFIG_SYS_I2C_RCAR_I2C) += rcar_i2c.o diff --git a/drivers/i2c/ocores_i2c.c b/drivers/i2c/ocores_i2c.c new file mode 100644 index 00000000000..c4f2cc43f9e --- /dev/null +++ b/drivers/i2c/ocores_i2c.c @@ -0,0 +1,637 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * ocores-i2c.c: I2C bus driver for OpenCores I2C controller + * (https://opencores.org/projects/i2c) + * + * (C) Copyright Peter Korsgaard <peter@korsgaard.com> + * + * Copyright (C) 2020 SiFive, Inc. + * Pragnesh Patel <pragnesh.patel@sifive.com> + * + * Support for the GRLIB port of the controller by + * Andreas Larsson <andreas@gaisler.com> + */ + +#include <common.h> +#include <asm/io.h> +#include <clk.h> +#include <dm.h> +#include <dm/device_compat.h> +#include <i2c.h> +#include <linux/io.h> +#include <linux/compat.h> +#include <linux/log2.h> +#include <linux/delay.h> + +/* registers */ +#define OCI2C_PRELOW 0 +#define OCI2C_PREHIGH 1 +#define OCI2C_CONTROL 2 +#define OCI2C_DATA 3 +#define OCI2C_CMD 4 /* write only */ +#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */ + +#define OCI2C_CTRL_IEN 0x40 +#define OCI2C_CTRL_EN 0x80 + +#define OCI2C_CMD_START 0x91 +#define OCI2C_CMD_STOP 0x41 +#define OCI2C_CMD_READ 0x21 +#define OCI2C_CMD_WRITE 0x11 +#define OCI2C_CMD_READ_ACK 0x21 +#define OCI2C_CMD_READ_NACK 0x29 +#define OCI2C_CMD_IACK 0x01 + +#define OCI2C_STAT_IF 0x01 +#define OCI2C_STAT_TIP 0x02 +#define OCI2C_STAT_ARBLOST 0x20 +#define OCI2C_STAT_BUSY 0x40 +#define OCI2C_STAT_NACK 0x80 + +#define STATE_DONE 0 +#define STATE_START 1 +#define STATE_WRITE 2 +#define STATE_READ 3 +#define STATE_ERROR 4 + +#define TYPE_OCORES 0 +#define TYPE_GRLIB 1 + +#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */ + +struct ocores_i2c_bus { + void __iomem *base; + u32 reg_shift; + u32 reg_io_width; + unsigned long flags; + struct i2c_msg *msg; + int pos; + int nmsgs; + int state; /* see STATE_ */ + struct clk clk; + int ip_clk_khz; + int bus_clk_khz; + void (*setreg)(struct ocores_i2c_bus *i2c, int reg, u8 value); + u8 (*getreg)(struct ocores_i2c_bus *i2c, int reg); +}; + +DECLARE_GLOBAL_DATA_PTR; + +/* Boolean attribute values */ +enum { + FALSE = 0, + TRUE, +}; + +static void oc_setreg_8(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + writeb(value, i2c->base + (reg << i2c->reg_shift)); +} + +static void oc_setreg_16(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + writew(value, i2c->base + (reg << i2c->reg_shift)); +} + +static void oc_setreg_32(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + writel(value, i2c->base + (reg << i2c->reg_shift)); +} + +static void oc_setreg_16be(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + out_be16(i2c->base + (reg << i2c->reg_shift), value); +} + +static void oc_setreg_32be(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + out_be32(i2c->base + (reg << i2c->reg_shift), value); +} + +static inline u8 oc_getreg_8(struct ocores_i2c_bus *i2c, int reg) +{ + return readb(i2c->base + (reg << i2c->reg_shift)); +} + +static inline u8 oc_getreg_16(struct ocores_i2c_bus *i2c, int reg) +{ + return readw(i2c->base + (reg << i2c->reg_shift)); +} + +static inline u8 oc_getreg_32(struct ocores_i2c_bus *i2c, int reg) +{ + return readl(i2c->base + (reg << i2c->reg_shift)); +} + +static inline u8 oc_getreg_16be(struct ocores_i2c_bus *i2c, int reg) +{ + return in_be16(i2c->base + (reg << i2c->reg_shift)); +} + +static inline u8 oc_getreg_32be(struct ocores_i2c_bus *i2c, int reg) +{ + return in_be32(i2c->base + (reg << i2c->reg_shift)); +} + +static inline void oc_setreg(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + i2c->setreg(i2c, reg, value); +} + +static inline u8 oc_getreg(struct ocores_i2c_bus *i2c, int reg) +{ + return i2c->getreg(i2c, reg); +} + +static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg) +{ + return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0); +} + +static void ocores_process(struct ocores_i2c_bus *i2c, u8 stat) +{ + struct i2c_msg *msg = i2c->msg; + + if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) { + /* stop has been sent */ + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); + return; + } + + /* error? */ + if (stat & OCI2C_STAT_ARBLOST) { + i2c->state = STATE_ERROR; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + + if (i2c->state == STATE_START || i2c->state == STATE_WRITE) { + i2c->state = + (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE; + + if (stat & OCI2C_STAT_NACK) { + i2c->state = STATE_ERROR; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + } else { + msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA); + } + + /* end of msg? */ + if (i2c->pos == msg->len) { + i2c->nmsgs--; + i2c->msg++; + i2c->pos = 0; + msg = i2c->msg; + + if (i2c->nmsgs) { /* end? */ + /* send start? */ + if (!(msg->flags & I2C_M_NOSTART)) { + u8 addr = i2c_8bit_addr_from_msg(msg); + + i2c->state = STATE_START; + + oc_setreg(i2c, OCI2C_DATA, addr); + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); + return; + } + i2c->state = (msg->flags & I2C_M_RD) + ? STATE_READ : STATE_WRITE; + } else { + i2c->state = STATE_DONE; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + } + + if (i2c->state == STATE_READ) { + oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len - 1) ? + OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK); + } else { + oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]); + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE); + } +} + +static irqreturn_t ocores_isr(int irq, void *dev_id) +{ + struct ocores_i2c_bus *i2c = dev_id; + u8 stat = oc_getreg(i2c, OCI2C_STATUS); + + if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) { + if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY)) + return IRQ_NONE; + } else if (!(stat & OCI2C_STAT_IF)) { + return IRQ_NONE; + } + ocores_process(i2c, stat); + + return IRQ_HANDLED; +} + +/** + * Wait until something change in a given register + * @i2c: ocores I2C device instance + * @reg: register to query + * @mask: bitmask to apply on register value + * @val: expected result + * @msec: timeout in msec + * + * Timeout is necessary to avoid to stay here forever when the chip + * does not answer correctly. + * + * Return: 0 on success, -ETIMEDOUT on timeout + */ +static int ocores_wait(struct ocores_i2c_bus *i2c, + int reg, u8 mask, u8 val, + const unsigned long msec) +{ + u32 count = 0; + + while (1) { + u8 status = oc_getreg(i2c, reg); + + if ((status & mask) == val) + break; + + udelay(1); + count += 1; + + if (count == (1000 * msec)) + return -ETIMEDOUT; + } + return 0; +} + +/** + * Wait until is possible to process some data + * @i2c: ocores I2C device instance + * + * Used when the device is in polling mode (interrupts disabled). + * + * Return: 0 on success, -ETIMEDOUT on timeout + */ +static int ocores_poll_wait(struct ocores_i2c_bus *i2c) +{ + u8 mask; + int err; + + if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) { + /* transfer is over */ + mask = OCI2C_STAT_BUSY; + } else { + /* on going transfer */ + mask = OCI2C_STAT_TIP; + /* + * We wait for the data to be transferred (8bit), + * then we start polling on the ACK/NACK bit + */ + udelay((8 * 1000) / i2c->bus_clk_khz); + } + + /* + * once we are here we expect to get the expected result immediately + * so if after 1ms we timeout then something is broken. + */ + err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, 1); + if (err) + debug("%s: STATUS timeout, bit 0x%x did not clear in 1ms\n", + __func__, mask); + return err; +} + +/** + * It handles an IRQ-less transfer + * @i2c: ocores I2C device instance + * + * Even if IRQ are disabled, the I2C OpenCore IP behavior is exactly the same + * (only that IRQ are not produced). This means that we can re-use entirely + * ocores_isr(), we just add our polling code around it. + * + * It can run in atomic context + */ +static void ocores_process_polling(struct ocores_i2c_bus *i2c) +{ + while (1) { + irqreturn_t ret; + int err; + + err = ocores_poll_wait(i2c); + if (err) { + i2c->state = STATE_ERROR; + break; /* timeout */ + } + + ret = ocores_isr(-1, i2c); + if (ret == IRQ_NONE) { + break; /* all messages have been transferred */ + } else { + if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) + if (i2c->state == STATE_DONE) + break; + } + } +} + +static int ocores_xfer_core(struct ocores_i2c_bus *i2c, + struct i2c_msg *msgs, int num, bool polling) +{ + u8 ctrl; + + ctrl = oc_getreg(i2c, OCI2C_CONTROL); + + if (polling) + oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~OCI2C_CTRL_IEN); + + i2c->msg = msgs; + i2c->pos = 0; + i2c->nmsgs = num; + i2c->state = STATE_START; + + oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg)); + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); + + if (polling) + ocores_process_polling(i2c); + + return (i2c->state == STATE_DONE) ? num : -EIO; +} + +static int ocores_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) +{ + struct ocores_i2c_bus *bus = dev_get_priv(dev); + int ret; + + debug("i2c_xfer: %d messages\n", nmsgs); + + ret = ocores_xfer_core(bus, msg, nmsgs, 1); + + if (ret != nmsgs) { + debug("i2c_write: error sending\n"); + return -EREMOTEIO; + } + + return 0; +} + +static int ocores_i2c_enable_clk(struct udevice *dev) +{ + struct ocores_i2c_bus *bus = dev_get_priv(dev); + ulong clk_rate; + int ret; + + ret = clk_get_by_index(dev, 0, &bus->clk); + if (ret) + return -EINVAL; + + ret = clk_enable(&bus->clk); + if (ret) + return ret; + + clk_rate = clk_get_rate(&bus->clk); + if (!clk_rate) + return -EINVAL; + + bus->ip_clk_khz = clk_rate / 1000; + + clk_free(&bus->clk); + + return 0; +} + +static int ocores_init(struct udevice *dev, struct ocores_i2c_bus *bus) +{ + int prescale; + int diff; + u8 ctrl = oc_getreg(bus, OCI2C_CONTROL); + + /* make sure the device is disabled */ + ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN); + oc_setreg(bus, OCI2C_CONTROL, ctrl); + + prescale = (bus->ip_clk_khz / (5 * bus->bus_clk_khz)) - 1; + prescale = clamp(prescale, 0, 0xffff); + + diff = bus->ip_clk_khz / (5 * (prescale + 1)) - bus->bus_clk_khz; + if (abs(diff) > bus->bus_clk_khz / 10) { + debug("Unsupported clock settings: core: %d KHz, bus: %d KHz\n", + bus->ip_clk_khz, bus->bus_clk_khz); + return -EINVAL; + } + + oc_setreg(bus, OCI2C_PRELOW, prescale & 0xff); + oc_setreg(bus, OCI2C_PREHIGH, prescale >> 8); + + /* Init the device */ + oc_setreg(bus, OCI2C_CMD, OCI2C_CMD_IACK); + oc_setreg(bus, OCI2C_CONTROL, ctrl | OCI2C_CTRL_EN); + + return 0; +} + +/* + * Read and write functions for the GRLIB port of the controller. Registers are + * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one + * register. The subsequent registers have their offsets decreased accordingly. + */ +static u8 oc_getreg_grlib(struct ocores_i2c_bus *i2c, int reg) +{ + u32 rd; + int rreg = reg; + + if (reg != OCI2C_PRELOW) + rreg--; + rd = in_be32(i2c->base + (rreg << i2c->reg_shift)); + if (reg == OCI2C_PREHIGH) + return (u8)(rd >> 8); + else + return (u8)rd; +} + +static void oc_setreg_grlib(struct ocores_i2c_bus *i2c, int reg, u8 value) +{ + u32 curr, wr; + int rreg = reg; + + if (reg != OCI2C_PRELOW) + rreg--; + if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) { + curr = in_be32(i2c->base + (rreg << i2c->reg_shift)); + if (reg == OCI2C_PRELOW) + wr = (curr & 0xff00) | value; + else + wr = (((u32)value) << 8) | (curr & 0xff); + } else { + wr = value; + } + out_be32(i2c->base + (rreg << i2c->reg_shift), wr); +} + +static int ocores_i2c_set_bus_speed(struct udevice *dev, unsigned int speed) +{ + int prescale; + int diff; + struct ocores_i2c_bus *bus = dev_get_priv(dev); + + /* speed in Khz */ + speed = speed / 1000; + + prescale = (bus->ip_clk_khz / (5 * speed)) - 1; + prescale = clamp(prescale, 0, 0xffff); + + diff = bus->ip_clk_khz / (5 * (prescale + 1)) - speed; + if (abs(diff) > speed / 10) { + debug("Unsupported clock settings: core: %d KHz, bus: %d KHz\n", + bus->ip_clk_khz, speed); + return -EINVAL; + } + + oc_setreg(bus, OCI2C_PRELOW, prescale & 0xff); + oc_setreg(bus, OCI2C_PREHIGH, prescale >> 8); + + bus->bus_clk_khz = speed; + return 0; +} + +int ocores_i2c_get_bus_speed(struct udevice *dev) +{ + struct ocores_i2c_bus *bus = dev_get_priv(dev); + + return (bus->bus_clk_khz * 1000); +} + +static const struct dm_i2c_ops ocores_i2c_ops = { + .xfer = ocores_i2c_xfer, + .set_bus_speed = ocores_i2c_set_bus_speed, + .get_bus_speed = ocores_i2c_get_bus_speed, +}; + +static int ocores_i2c_probe(struct udevice *dev) +{ + struct ocores_i2c_bus *bus = dev_get_priv(dev); + bool clock_frequency_present; + u32 val; + u32 clock_frequency_khz; + int ret; + + bus->base = (void __iomem *)devfdt_get_addr(dev); + + if (dev_read_u32(dev, "reg-shift", &bus->reg_shift)) { + /* no 'reg-shift', check for deprecated 'regstep' */ + ret = dev_read_u32(dev, "regstep", &val); + if (ret) { + dev_err(dev, + "missing both reg-shift and regstep property: %d\n", ret); + return -EINVAL; + } else { + bus->reg_shift = ilog2(val); + dev_warn(dev, + "regstep property deprecated, use reg-shift\n"); + } + } + + if (dev_read_u32(dev, "clock-frequency", &val)) { + bus->bus_clk_khz = 100; + clock_frequency_present = FALSE; + } else { + bus->bus_clk_khz = val / 1000; + clock_frequency_khz = val / 1000; + clock_frequency_present = TRUE; + } + + ret = ocores_i2c_enable_clk(dev); + if (ret) + return ret; + + if (bus->ip_clk_khz == 0) { + if (dev_read_u32(dev, "opencores,ip-clock-frequency", &val)) { + if (!clock_frequency_present) { + dev_err(dev, + "Missing required parameter 'opencores,ip-clock-frequency'\n"); + clk_disable(&bus->clk); + return -ENODEV; + } + + bus->ip_clk_khz = clock_frequency_khz; + dev_warn(dev, + "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n"); + } else { + bus->ip_clk_khz = val / 1000; + if (clock_frequency_present) + bus->bus_clk_khz = clock_frequency_khz; + } + } + + bus->reg_io_width = dev_read_u32_default(dev, "reg-io-width", 1); + + if (dev_get_driver_data(dev) == TYPE_GRLIB) { + debug("GRLIB variant of i2c-ocores\n"); + bus->setreg = oc_setreg_grlib; + bus->getreg = oc_getreg_grlib; + } + + if (!bus->setreg || !bus->getreg) { + bool be = (cpu_to_be32(0x12345678) == 0x12345678); + + switch (bus->reg_io_width) { + case 1: + bus->setreg = oc_setreg_8; + bus->getreg = oc_getreg_8; + break; + + case 2: + bus->setreg = be ? oc_setreg_16be : oc_setreg_16; + bus->getreg = be ? oc_getreg_16be : oc_getreg_16; + break; + + case 4: + bus->setreg = be ? oc_setreg_32be : oc_setreg_32; + bus->getreg = be ? oc_getreg_32be : oc_getreg_32; + break; + + default: + debug("Unsupported I/O width (%d)\n", + bus->reg_io_width); + ret = -EINVAL; + goto err_clk; + } + } + + /* + * Set OCORES_FLAG_BROKEN_IRQ to enable workaround for + * FU540-C000 SoC in polling mode. + * Since the SoC does have an interrupt, its DT has an interrupt + * property - But this should be bypassed as the IRQ logic in this + * SoC is broken. + */ + + if (device_is_compatible(dev, "sifive,fu540-c000-i2c")) + bus->flags |= OCORES_FLAG_BROKEN_IRQ; + + ret = ocores_init(dev, bus); + if (ret) + goto err_clk; + + return 0; + +err_clk: + clk_disable(&bus->clk); + return ret; +} + +static const struct udevice_id ocores_i2c_ids[] = { +{ .compatible = "opencores,i2c-ocores", .data = TYPE_OCORES }, +{ .compatible = "aeroflexgaisler,i2cmst", .data = TYPE_GRLIB }, +{ .compatible = "sifive,fu540-c000-i2c" }, +{ .compatible = "sifive,i2c0" }, +}; + +U_BOOT_DRIVER(i2c_ocores) = { + .name = "i2c_ocores", + .id = UCLASS_I2C, + .of_match = ocores_i2c_ids, + .probe = ocores_i2c_probe, + .priv_auto_alloc_size = sizeof(struct ocores_i2c_bus), + .ops = &ocores_i2c_ops, +}; |